MIG welding systems have been widely used in the United States and other places around the world since at least the 1960's. In MIG type welding, a welding wire is utilized to provide a molten metal pool in order to join metal pieces together. MIG welding systems utilize a continuous welding wire that is rolled onto a spool and fed through coaxial welding cable to the welding gun. A MIG welding gun has a handle having a trigger that when pressed, gas and wire are fed to the gun from the attached cable and to the welding tip. Because of the continuous welding wire, MIG welding systems are generally faster than Tungsten Inert Gas (TIG) systems or conventional stick welding systems that utilize individual welding rods.
The primary components of a MIG welding system which are well known to those skilled in the art, are shown in FIG. 1 and generally indicated at 8. The welding power source 10 connects to an AC power supply 12 which is shown diagrammatically.
Also connected to the welding power source 10 is a high pressure gas cylinder 14 which typically contains an inert gas such as argon or perhaps a combination of argon and carbon dioxide. A shut-off valve 16 is attached to the high pressure cylinder 14. A regulator 18 is connected via piping to the valve 16 and typically reduces the pressure of the inert gas downstream from the regulator. A pressure gauge 20 provides a visual display of the gas pressure in the cylinder 14. A high pressure hose 22 provides fluid communication for the inert gas to the welding power source 10. The flow meter 21 is in fluid communication with the regulator 18 and the high pressure hose 22.
The welding wire 24 is coiled on a spool 26. The welding wire 24 can be a copper coated ferrous wire, a stainless steel wire, a flux cored wire, etc. The spool 26 is mounted on a reel 28 which is typically positioned on top of the welding power source 10. The welding wire feeder assembly 30 advances the welding wire from the spool 26 to the welding gun 1. The welding wire feeder assembly 30 includes two or more rollers 32 and 34 which grip the welding wire 24 and mechanically advance it from the spool 26 to the welding gun 1.
Control wires 9 are releasably connected on one end to the rear connector 40 and on the other end to the welding power source 10 or to the wire feeder assembly 30. The trigger 55 on the welding gun 1 actuates the welding power source 10 by closing the control circuit. Control wires 9 connect the trigger 55 to the welding power source 10, and are typically encased in the welding cable 42.
The coaxial welding cable 42 connects on one end to the rear connector 40 and on the other end to the welding gun 1. In this example, the workpiece 47 consists of a first plate 44 and a second plate 46 which are being welded together. A ground clamp 48 is attached to the workpiece 47 to complete the electrical circuit. A cable 50 electrically connects the welding power source 10 with the ground clamp 48.
In a typical MIG system, the workpiece is negative and the welding wire 24 is positive. The electrical circuit for a typical MIG welding system is completed as follows: The welding power source 10 connects to a cable 50 at the end of which is the ground clamp 48. The ground clamp 48 is manually attached by the welder to the workpiece 47. An electrical arc is created between the workpiece 47 and the welding wire 24 which causes the welding wire to melt into a molten pool thus joining the plats 44 and 46.
In many applications the MIG welding gun provides much less flexibility than the traditional welding system. In a MIG welding gun, the cable that is coupled to the welding gun is generally heavy and resistant. A welder must constantly drag the heavy cable while twisting and turning the gun. As a consequence, the MIG welding gun is difficult to manipulate, necessitating an increased effort on the part of the welder, particularly to the hands, wrists, forearms, elbow, upper arm, and shoulder. Current MIG welding guns resist the supination and pronation movements required for many welding projects. The addition of repetitive twisting type motions subjects the welder to the risk of occupational injuries such as carpel tunnel, cubital tunnel syndrome and rotator cuff injuries. The present invention is an improvement over previous MIG welding systems.